I've often thought about how Quidditch could be made into a better game, without simply getting rid of Seekers and Snitches. My idea:

• Each team has three Chasers; at any time, one of them is acting as Seeker.
• There are five Snitches, each of which is worth 50 points when caught.
• When a Seeker catches a Snitch, (s)he becomes a Chaser, and the next Chaser in line becomes the new Seeker.
• A caught Snitch flies to the goals of the team who caught it; it places itself in the exact center of the leftmost or rightmost goal hoop (at the option of the team's Keeper) and renders itself immovable, so it can block the Quaffle when it's thrown too close to the center of the goal.
• The game ends when one team has caught three Snitches.

By these rules, all the players must make active contributions to the goal-scoring game, and catching more Snitches earlier confers a significant advantage, but not an unovercomeable one.

BELATED EDIT: I must also add, so long as we're talking about Quidditch rules:

• Goals are worth one point and Snitches are worth five points everywhere except for official Hogwarts games. It really bugs me when the possible point increments in a game aren't coprime.